Developmental changes in delta-aminolevulinic acid dehydratase (ALAD) activity and blood reticulocyte percent in the...

A correlation between blood reticulocyte percent and the activity of erythrocytic delta-aminolevulinic acid dehydratase (ALAD) in the developing rat has been established during the progression from a state of macrocytic hypochromic anemia at birth to a normocytic normochromic state at puberty, and finally to a state just prior to adulthood at which the reticulocyte percent had stabilized. Both reticulocyte percent and erythrocytic ALAD activity was found to decrease with age, rapidly at first until a normocytic normochromic state was reached at puberty and then more slowly until just before adulthood when both plateaued. A direct, linear correlation between erythrocytic ALAD activity and blood reticulocyte percent was found with a P value of less than 0.001. These findings should be carefully considered when using the rat as a model for lead poisoning and possibly for other disorders of heme biosynthesis.